Doherty Institute - Research Publications
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ItemHeterogeneity in HIV and cellular transcription profiles in cell line models of latent and productive infection: implications for HIV latency(BMC, 2019-11-11)BACKGROUND: HIV-infected cell lines are widely used to study latent HIV infection, which is considered the main barrier to HIV cure. We hypothesized that these cell lines differ from each other and from cells from HIV-infected individuals in the mechanisms underlying latency. RESULTS: To quantify the degree to which HIV expression is inhibited by blocks at different stages of HIV transcription, we employed a recently-described panel of RT-ddPCR assays to measure levels of 7 HIV transcripts ("read-through," initiated, 5' elongated, mid-transcribed/unspliced [Pol], distal-transcribed [Nef], polyadenylated, and multiply-sliced [Tat-Rev]) in bulk populations of latently-infected (U1, ACH-2, J-Lat) and productively-infected (8E5, activated J-Lat) cell lines. To assess single-cell variation and investigate cellular genes associated with HIV transcriptional blocks, we developed a novel multiplex qPCR panel and quantified single cell levels of 7 HIV targets and 89 cellular transcripts in latently- and productively-infected cell lines. The bulk cell HIV transcription profile differed dramatically between cell lines and cells from ART-suppressed individuals. Compared to cells from ART-suppressed individuals, latent cell lines showed lower levels of HIV transcriptional initiation and higher levels of polyadenylation and splicing. ACH-2 and J-Lat cells showed different forms of transcriptional interference, while U1 cells showed a block to elongation. Single-cell studies revealed marked variation between/within cell lines in expression of HIV transcripts, T cell phenotypic markers, antiviral factors, and genes implicated in latency. Expression of multiply-spliced HIV Tat-Rev was associated with expression of cellular genes involved in activation, tissue retention, T cell transcription, and apoptosis/survival. CONCLUSIONS: HIV-infected cell lines differ from each other and from cells from ART-treated individuals in the mechanisms governing latent HIV infection. These differences in viral and cellular gene expression must be considered when gauging the suitability of a given cell line for future research on HIV. At the same time, some features were shared across cell lines, such as low expression of antiviral defense genes and a relationship between productive infection and genes involved in survival. These features may contribute to HIV latency or persistence in vivo, and deserve further study using novel single cell assays such as those described in this manuscript.
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ItemDelays in Patient Presentation and Diagnosis for Buruli Ulcer (Mycobacterium ulcerans Infection) in Victoria, Australia, 2011-2017.(MDPI AG, 2019-07-04)Uncertainty regarding transmission pathways and control measures makes prompt presentation and diagnosis for Buruli ulcer critical. To examine presentation and diagnosis delays in Victoria, Australia, we conducted a retrospective study of 703 cases notified between 2011 and 2017, classified as residing in an endemic (Mornington Peninsula; Bellarine Peninsula; South-east Bayside and Frankston) or non-endemic area. Overall median presentation delay was 30 days (IQR 14-60 days), with no significant change over the study period (p = 0.11). There were significant differences in median presentation delay between areas of residence (p = 0.02), but no significant change over the study period within any area. Overall median diagnosis delay was 10 days (IQR 0-40 days), with no significant change over the study period (p = 0.13). There were significant differences in median diagnosis delay between areas (p < 0.001), but a significant decrease over time only on the Mornington Peninsula (p < 0.001). On multivariable analysis, being aged <15 or >65 years; having non-ulcerative disease; and residing in the Bellarine Peninsula or South-East Bayside (compared to non-endemic areas) were significantly associated with shorter presentation delay. Residing in the Bellarine or Mornington Peninsula and being notified later in the study period were significantly associated with shorter diagnosis delay. To reduce presentation and diagnosis delays, awareness of Buruli ulcer must be raised with the public and medical professionals, particularly those based outside established endemic areas.
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ItemCirculating Vaccine-Derived Poliovirus Type 1 and Outbreak Response - Papua New Guinea, 2018(CENTERS DISEASE CONTROL, 2019-02-08)
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ItemThe emergence and spread of one Coxsackievirus A16 Genogroup D novel recombinant strain that caused a clustering HFMD outbreak in Shanghai, China, 2016(NATURE PUBLISHING GROUP, 2018-07-18)
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ItemPredicting HBsAg clearance in genotype A chronic hepatitis B using HBsAg epitope profiling: A biomarker for functional cure(WILEY, 2019-11)BACKGROUND AND AIM: Functional cure is the major goal of chronic hepatitis B (CHB) therapy though few biomarkers predict this outcome. HBsAg epitope occupancy can be influenced by therapeutic and immune pressure. The aim of this study was to map the HBsAg epitope profiles during long-term nucleos(t)ide analogue therapy in patients with genotype A CHB, in the context of HBsAg loss (SL)/seroconversion. METHODS: We evaluated 25 genotype A CHB patients in the GS-US-174-0103 trial of HBeAg-positive CHB patients treated with tenofovir or adefovir for 4 years, 14 who achieved SL whilst 11 had no change. We epitope mapped the major domains of HBsAg to identify those patients with HBsAg clearance profile (CP) (loss of binding at both loops 1 and 2 epitopes of the 'a' determinant) vs non-clearance profile (no change in epitope recognition, or loss of epitope binding at one loop only), correlating this to on-treatment HBsAg responses. Complexed anti-HBs was also measured. RESULTS: Analysis of the HBsAg epitope profiles of the 25 patients at baseline identified no predictive correlation with SL. In contrast, analysis at week 48 and end of study (week 192) or prior to SL identified significant predictive associations between development of HBsAg CPs and outcome of functional cure. The detection of a CP also correlated with the development of an alanine aminotransferase flare and detection of anti-HBs complexed with HBsAg. CONCLUSION: The detection of HBsAg CPs by epitope mapping represents a novel viral biomarker, reflecting an emerging anti-HBs selection pressure prior to functional cure.
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ItemReview of 20 years of human acute Q fever notifications in Victoria, 1994-2013(WILEY, 2018-06)OBJECTIVE: To describe the epidemiological and clinical features of acute Q fever in Victoria from 1994 to 2013. DESIGN: Retrospective case series and spatiotemporal analyses of human notification data. METHODS: Records for all confirmed cases of Q fever in Victoria notified between 1994 and 2013 were reviewed. Clinical and epidemiological features of the cases were described and spatiotemporal analysis undertaken for all cases potentially acquired within Victoria. RESULTS: A total of 659 confirmed acute Q fever cases were notified over the study period. Cases decreased at a rate of 4.2% per annum (95% confidence interval (CI): 0.9, 7.4%). Notification rates decreased among abattoir workers and related occupations by 10.9% per annum (95% CI: 6.5, 15.0%), whereas those among dairy farmers rose by 14.9% per annum (95% CI: 4.7, 26.0%). The mean age of cases increased over the study period while the ratio of male to female cases decreased. Spatiotemporal analysis suggested endemic transmission, with 55% of cases associated with abattoirs and related businesses and a further 30% considered to have acquired the infection locally. In addition to abattoir-associated clusters, important foci for local acquisition included South and East Gippsland, Wodonga and an outbreak centred on a dairy goat farm west of Melbourne. CONCLUSIONS: There has been a reduction in cases of acute Q fever in Victoria over the past 20 years and a changing epidemiology with respect to age, sex and acquisition source. Epidemiological and spatiotemporal analyses suggested a low level of endemic transmission within the state, with multiple foci of increased zoonotic transmission.
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ItemThe association of rainfall and Buruli ulcer in southeastern Australia(PUBLIC LIBRARY SCIENCE, 2018-09)BACKGROUND: Buruli ulcer has been increasing in incidence in southeastern Australia with unclear transmission mechanisms. We aimed to investigate the link between rainfall and case numbers in two endemic areas of the state of Victoria; the Bellarine and Mornington Peninsulas. METHODOLOGY: We created yearly and monthly graphs comparing rainfall with local Buruli ulcer incidence for the period 2004-2016 by endemic region and then considered a range of time lag intervals of 0-24 months to investigate patterns of correlation. CONCLUSIONS: Optimal positive correlation for the Bellarine Peninsula occurred with a 12-month prior rainfall lag, however, no significant correlation was observed on the Mornington Peninsula for any time lag. These results provide an update in evidence to further explore transmission mechanisms which may differ between these geographically proximate endemic regions.