Biology subjects

Davis, C. T.

Publications and source records attributed to Davis, C. T..

4 recordsLinked to original sources

bioRxiv2022

Interspecies transmission from pigs to ferrets of antigenically distinct swine H1 influenza A viruses with loss in reactivity to human vaccine virus antisera as measures of relative zoonotic risk

During the last decade, endemic swine H1 influenza A viruses (IAV) from six different genetic clades of the hemagglutinin gene caused zoonotic infections in humans. The majority of zoonotic events with swine IAV were restricted to a single case with no subsequent transmission. However, repeated introduction of human-seasonal H1N1, continual reassortment between endemic swine IAV, and subsequent drift in the swine host resulted in highly diverse swine IAV with human-origin genes that may become a risk to the human population. To prepare for the potential of a future swine-origin IAV pandemic in humans, public health laboratories selected candidate vaccine viruses (CVV) for use as vaccine seed strains. To assess the pandemic risk of contemporary US swine H1N1 or H1N2 strains, we quantified the genetic diversity of swine H1 HA genes, and identified representative strains from each circulating clade. We then characterized the representative swine IAV against human seasonal vaccine and CVV strains using ferret antisera in hemagglutination inhibition assays (HI). HI assays revealed that 1A.3.3.2 (pdm) and 1B.2.1 (delta-2) demonstrated strong cross reactivity to human seasonal vaccines or CVVs. However, swine IAV from three clades that represent more than 50% of the detected swine IAVs in the USA showed significant reduction in cross-reactivity compared to the closest CVV virus: 1A.1.1.3 (alpha-deletion), 1A.3.3.3-clade 3 (gamma), and 1B.2.2.1 (delta-1a). Representative viruses from these three clades were further characterized in a pig-to-ferret transmission model and shown to exhibit variable transmission efficiency. Our data prioritize specific genotypes of swine H1N1 and H1N2 to further investigate in the risk they pose to the human population. ImportanceInfluenza A virus (IAV) is endemic in both humans and pigs and there is occasional bidirectional transmission of viruses. The process of interspecies transmission introduces novel viruses that increases the viral diversity in each host, impacting viral ecology and challenging control efforts through vaccine programs. Swine-origin IAVs have the potential to cause human pandemics, and pandemic preparation efforts include the identification and generation of candidate vaccine viruses (CVV) derived from epidemiologically relevant swine IAV surface proteins. The CVVs are derived from swine IAV detected and isolated in humans, and are updated infrequently; consequently the efficacy of these vaccines against contemporary swine IAV is unclear given rapid turnover and change of diversity. In this report we perform a risk assessment of contemporary swine H1 IAVs, determine whether current CVVs cross-react, and illustrate how swine-origin IAV replicate, transmit, and cause disease in a swine-to-ferret model system. In doing so, we identify the swine IAV that have lost cross-reactivity to current pandemic preparedness vaccines and demonstrate the utility of swine-to-ferret transmission experiments to further inform risk assessment.

microbiology↗

bioRxiv2020

Functional immune mapping with deep-learning enabled phenomics applied to immunomodulatory and COVID-19 drug discovery

Development of accurate disease models and discovery of immune-modulating drugs is challenged by the immune systems highly interconnected and context-dependent nature. Here we apply deep-learning-driven analysis of cellular morphology to develop a scalable "phenomics" platform and demonstrate its ability to identify dose-dependent, high-dimensional relationships among and between immunomodulators, toxins, pathogens, genetic perturbations, and small and large molecules at scale. High-throughput screening on this platform demonstrates rapid identification and triage of hits for TGF-{beta}- and TNF--driven phenotypes. We deploy the platform to develop phenotypic models of active SARS-CoV-2 infection and of COVID-19-associated cytokine storm, surfacing compounds with demonstrated clinical benefit and identifying several new candidates for drug repurposing. The presented library of images, deep learning features, and compound screening data from immune profiling and COVID-19 screens serves as a deep resource for immune biology and cellular-model drug discovery with immediate impact on the COVID-19 pandemic.

immunology↗

bioRxiv2020

Identification of potential treatments for COVID-19 through artificial intelligence-enabled phenomic analysis of human cells infected with SARS-CoV-2

To identify potential therapeutic stop-gaps for SARS-CoV-2, we evaluated a library of 1,670 approved and reference compounds in an unbiased, cellular image-based screen for their ability to suppress the broad impacts of the SARS-CoV-2 virus on phenomic profiles of human renal cortical epithelial cells using deep learning. In our assay, remdesivir is the only antiviral tested with strong efficacy, neither chloroquine nor hydroxychloroquine have any beneficial effect in this human cell model, and a small number of compounds not currently being pursued clinically for SARS-CoV-2 have efficacy. We observed weak but beneficial class effects of {beta}-blockers, mTOR/PI3K inhibitors and Vitamin D analogues and a mild amplification of the viral phenotype with {beta}-agonists.

systems biology↗

bioRxiv2019

Mitigating Pandemic Risk with Influenza A Virus Field Surveillance at a Swine-Human Interface

Working overnight at a large swine exhibition, we identified an influenza A virus (IAV) outbreak in swine, nanopore-sequenced 13 IAV genomes from samples collected, and in real-time, determined that these viruses posed a novel risk to humans due to genetic mismatches between the viruses and current pre-pandemic candidate vaccine viruses (CVV). We developed and used a portable IAV sequencing and analysis platform called Mia (Mobile Influenza Analysis) to complete and characterize full-length consensus genomes approximately 18 hours after unpacking the mobile lab. Swine are important animal IAV reservoirs that have given rise to pandemic viruses via zoonotic transmission. Genomic analyses of IAV in swine are critical to understanding pandemic risk of viruses in this reservoir, and characterization of viruses circulating in exhibition swine enables rapid comparison to current seasonal influenza vaccines and CVVs. The Mia system rapidly identified three genetically distinct swine IAV lineages from three subtypes: A(H1N1), A(H3N2) and A(H1N2). Additional analysis of the HA protein sequences of the A(H1N2) viruses identified >30 amino acid differences between the HA1 portion of the hemagglutinin of these viruses and the most closely related pre-2009 CVV. All virus sequences were emailed to colleagues at CDC who initiated development of a synthetically derived CVV designed to provide an optimal antigenic match with the viruses detected in the exhibition. In subsequent months, this virus caused 13 infections in humans, and was the dominant variant virus in the US detected in 2018. Had this virus caused a severe outbreak or pandemic, our proactive surveillance efforts and CVV derivation would have provided an approximate 8 week time advantage for vaccine manufacturing. This is the first report of the use of field-derived nanopore sequencing data to initiate a real-time, actionable public health countermeasure.

microbiology↗