Project description:Fast, high-throughput methods for measuring the level and duration of protective immune responses to SARS-CoV-2 are needed to anticipate the risk of breakthrough infections. Here we report the development of two quantitative PCR assays for SARS-CoV-2- specific T cell activation. The assays are rapid, internally normalized and probe-based: qTACT requires RNA extraction and dqTACT avoids sample preparation steps. Both assays rely on the quantification of CXCL10 messenger RNA, a chemokine whose expression is strongly correlated with activation of antigen-specific T cells. On restimulation of whole-blood cells with SARS-CoV-2 viral antigens, viral-specific T cells secrete IFN-γ, which stimulate monocytes to produce CXCL10. CXCL10 mRNA can thus serve as a proxy to quantify cellular immunity. Our assays may allow large-scale monitoring of the magnitude and duration of functional T cell immunity to SARS-CoV-2, thus helping to prioritize revaccination strategies in vulnerable populations.
Project description:Fast, high-throughput methods for measuring the level and duration of protective immune responses to SARS-CoV-2 are needed to anticipate the risk of breakthrough infections. Here we report the development of two quantitative PCR assays for SARS-CoV-2-specific T cell activation. The assays are rapid, internally normalized and probe-based: qTACT requires RNA extraction and dqTACT avoids sample preparation steps. Both assays rely on the quantification of CXCL10 messenger RNA, a chemokine whose expression is strongly correlated with activation of antigen-specific T cells. On restimulation of whole-blood cells with SARS-CoV-2 viral antigens, viral-specific T cells secrete IFN-γ, which stimulates monocytes to produce CXCL10. CXCL10 mRNA can thus serve as a proxy to quantify cellular immunity. Our assays may allow large-scale monitoring of the magnitude and duration of functional T cell immunity to SARS-CoV-2, thus helping to prioritize revaccination strategies in vulnerable populations.
Project description:Rapid Acceleration of Diagnostics - Radical (RADx-rad): A Scalable Aptamer-based Electrochemical Biosensor For Rapid Detection of SARS-CoV-2 From Saliva
Project description:Rapid Acceleration of Diagnostics - Radical (RADx-rad): A Scalable Aptamer-based Electrochemical Biosensor For Rapid Detection of SARS-CoV-2 From Saliva
Project description:The ongoing SARS-CoV-2 pandemic and subsequent demand for viral testing worldwide has led to major issues in scaling the efforts of diagnostic labs and even in securing basic supplies for collection and processing of samples. This has in turn led to worldwide efforts by the scientific community to establish improved protocols that are cheaper, more scalable, and not as resource intensive. One such effort resulted in an assay called “Swab-Seq”, which was so named because it was originally developed to work with dry nasal swab samples, but is actually flexible in terms of the sample type it can accommodate for testing. The assay adapts the existing gold standard (RNA extracted from a nasopharyngeal (NP) swab that is subjected to quantitative reverse transcription polymerase chain reaction, “qRT-PCR”) to a next-generation sequencing readout. By pairing this modification with extraction-free sampling techniques it is possible to achieve high scalability at low cost per sample, and a reasonable turnaround time for reporting results. We evaluated the effectiveness of this assay both on samples collected from asymptomatic individuals using the traditional NP swab and using alternative extraction-free sampling techniques, including saliva and a saline mouth gargle protocol, and found the assay to be highly sensitive (comparable to the standard qRT-PCR assay), flexible (adaptable to saliva and gargle samples stored at room temperature up to a week), and scalable (easily accommodating hundreds of samples at a time). Continued development in the future will lead to more effective testing regimes that reduce the burden of transmissible respiratory infections on the global community.
Project description:The SARS-CoV-2 virus is continuously evolving, with appearance of new variants characterized by multiple genomic mutations, some of which can affect functional properties, including infectivity, interactions with host immunity, and disease severity. The rapid spread of new SARS-CoV-2 variants has highlighted the urgency to trace the virus evolution, to help limit its diffusion, and to assess effectiveness of containment strategies. We propose here a PCR-based rapid, sensitive and low-cost allelic discrimination assay panel for the identification of SARS-CoV-2 genotypes, useful for detection in different sample types, such as nasopharyngeal swabs and wastewater. The tests carried out demonstrate that this in-house assay, whose results were confirmed by SARS-CoV-2 whole-genome sequencing, can detect variations in up to 10 viral genome positions at once and is specific and highly sensitive for identification of all tested SARS-CoV-2 clades, even in the case of samples very diluted and of poor quality, particularly difficult to analyze.
Project description:Here we present an inexpensive, rapid, and robust reverse-transcription loop-mediated isothermal amplification (RT-LAMP)-based severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection method that is easily scalable, enabling point-of-care facilities and clinical labs to determine results from patients' saliva directly in 30 minutes for less than $2 per reaction. The method uses a novel combination of widely available reagents that can be prepared in bulk, plated, and frozen and remain stable until samples are received. This innovation dramatically reduces preparation time, enabling high-throughput automation and testing with time to results (including setup) in less than 1 hour for 96 patient samples simultaneously when using a 384-well format. By using a dual reporter (phenol red pH indicator for end-point detection and SYTO-9 fluorescent dye for real time), the assay also provides internal validation of results and redundancy in the event of an instrument malfunction.