Infectious Diseases - Research Publications
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ItemNo Preview AvailableReprogrammed CRISPR-Cas13b suppresses SARS-CoV-2 replication and circumvents its mutational escape through mismatch tolerance( 2020)
ABSTRACT
Mutation-driven evolution of SARS coronavirus-2 (SARS-CoV-2) highlights the need for innovative approaches that simultaneously suppress viral replication and circumvent viral escape routes from host immunity and antiviral therapeutics. Here, we employed genome-wide computational prediction and singlenucleotide resolution screening to reprogram CRISPR-Cas13b against SARS-CoV-2 genomic and subgenomic RNAs. Reprogrammed Cas13b effectors targeting accessible regions of Spike and Nucleocapsid transcripts achieved >98% silencing efficiency in virus free-models. Further, optimized and multiplexed gRNAs suppressed viral replication by up to 90% in mammalian cells infected with replication-competent SARS-CoV-2. Unexpectedly, the comprehensive mutagenesis of guide-target interaction demonstrated that single-nucleotide mismatches do not impair the capacity of a potent single gRNA to simultaneously suppress ancestral and mutated SARS-CoV-2 in infected mammalian cells, including the highly infectious and globally disseminated Spike D614G mutant. The specificity, efficiency and rapid deployment properties of reprogrammed Cas13b described here provide a molecular blueprint of antiviral therapeutics to simultaneously suppress a wide range of SARS-CoV-2 mutants, and is readily adaptable to other emerging pathogenic viruses. -
ItemEvaluation of serological tests for SARS-CoV-2: Implications for serology testing in a low-prevalence setting( 2020)
Background
Robust serological assays are essential for long-term control of the COVID-19 pandemic. Many recently released point-of-care (PoCT) serological assays have been distributed with little pre-market validation.Methods
Performance characteristics for five PoCT lateral flow devices approved for use in Australia were compared to a commercial enzyme immunoassay (ELISA) and a recently described novel surrogate virus neutralisation test (sVNT).Results
Sensitivities for PoCT ranged from 51.8% (95% CI 43.1 to 60.4%) to 67.9% (95% CI 59.4–75.6%), and specificities from 95.6% (95% CI 89.2–98.8%) to 100.0% (95% CI 96.1–100.0%). Overall ELISA sensitivity for either IgA or IgG detection was 67.9% (95% CI 59.4–75.6), increasing to 93.8% (95% CI 85.0–98.3%) for samples > 14 days post symptom onset. Overall, sVNT sensitivity was 60.9% (95% CI 53.2–68.4%), rising to 91.2%% (95% CI 81.8–96.7%) for samples collected > 14 days post-symptom onset, with a specificity 94.4% (95% CI 89.2–97.5%),Conclusion
Performance characteristics for COVID-19 serological assays were generally lower than those reported by manufacturers. Timing of specimen collection relative to onset of illness or infection is crucial in the reporting of performance characteristics for COVID-19 serological assays. The optimal algorithm for implementing serological testing for COVID-19 remains to be determined, particularly in low-prevalence settings. -
ItemA randomized trial of vorinostat with treatment interruption after initiating antiretroviral therapy during acute HIV-1 infection(MEDISCRIPT LTD, 2020-09)OBJECTIVE AND DESIGN: A randomized, open-label pilot study in individuals treated with antiretroviral therapy (ART) since acute HIV infection (AHI) with a regimen including a histone deacetylase inhibitor to induce HIV from latency and control HIV replication during subsequent treatment interruption (TI). METHODS: Fifteen participants who initiated ART at AHI were randomized to vorinostat/hydroxychloroquine/maraviroc (VHM) plus ART (n = 10) or ART alone (n = 5). The VHM arm received three 14-day vorinostat cycles within 10 weeks before TI. ART was resumed for plasma viral load (VL) > 1,000 HIV RNA copies/mL. Primary outcome was proportion of participants on VHM + ART versus ART only with VL < 50 copies/mL for 24 weeks after TI. RESULTS: Fifteen participants on ART (median: 178 weeks: range 79-295) enrolled. Two on VHM + ART experienced serious adverse events. Fourteen participants underwent TI; all experienced VL rebound with no difference in time between arms: VHM + ART (n = 9) median: 4 weeks and ART only (n = 5) median: 5 weeks. VHM induced a 2.2-fold increase in VL (p = 0.008) by single-copy HIV RNA assay after the first cycle. Neopterin levels increased significantly following the first two cycles. After VHM treatment, the frequencies of peripheral blood mononuclear cells harboring total HIV DNA and cell-associated RNA were unchanged. All participants achieved VL suppression following ART re-initiation. CONCLUSIONS: Administration of VHM increased HIV VL in plasma, but this was not sustained. VHM did not impact time to viral rebound following TI and had no impact on the size of the HIV reservoir, suggesting that HIV reservoir elimination will require alternative treatment strategies.
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ItemNo Preview AvailableBreadth of concomitant immune responses prior to patient recovery: a case report of non-severe COVID-19(NATURE PORTFOLIO, 2020-04)