Project description:Genetic barrier to resistance: a critical parameter for efficacy of neutralizing monoclonal antibodies against SARS-CoV-2 in a non-human primate model
Project description:Severe acute respiratory syndrome virus (SARS-CoV) that lacks the envelope (E) gene (rSARS-CoV-ΔE) is attenuated in vivo [1,2]. To identify factors that contribute to rSARS-CoV-ΔE attenuation, gene expression in cells infected by SARS-CoV with or without E gene was compared. Twenty-five stress response genes were preferentially upregulated during infection in the absence of the E gene. In addition, genes involved in signal transduction, transcription, cell metabolism, immunoregulation, inflammation, apoptosis and cell cycle and differentiation were differentially regulated in cells infected with rSARS-CoV with or without the E gene. Administration of E protein in trans reduced the stress response in cells infected with rSARS-CoV-ΔE, with respiratory syncytial virus, or treated with drugs, such as tunicamycin and thapsigarcin that elicit cell stress by different mechanisms. In addition, SARS-CoV E protein down-regulated the signaling pathway inositol-requiring enzyme 1 (IRE-1) of the unfolded protein response, but not the PKR-like ER kinase (PERK) or activating transcription factor 6 (ATF-6) pathways, and reduced cell apoptosis. Overall, the activation of the IRE-1 pathway was not able to restore cell homeostasis, and apoptosis was induced probably as a meassure to protect the host by limiting virus production and dissemination. The expression of proinflammatory cytokines was reduced in rSARS-CoV-ΔE-infected cells compared to rSARS-CoV-infected cells, suggesting that the increase in stress responses and the reduction of inflammation in the absence of the E gene contributed to the attenuation of rSARS-CoV-ΔE. We used Affymetrix microarrays (Human Genome U133 plus 2.0) to compare global gene expression between SARS-CoV-infected, mock-infected and SARS-CoV-ΔE-infected cells. For ech type of sample three hybridizations were carried-out (independent biological replicates).
Project description:This project is aimed at characterizing the interactions of SARS-CoV-2 Spike protein and its variants with multiple full-length antibodies and monitoring the accompanying conformational dynamics. Different categories of antibodies are tested that recognize different domains of the Spike protein. The project aims at identifying the effects of weak, moderate and strong neutralizing antibodies on Spike protein and decipher their mechanisms of action. In addition to the direct binding effects, distal allosteric effects are also determined. A range of biophysical experiments, biochemical assays, and molecular dynamics simulations are used as orthogonal approaches. The rationale is to identify regions on the SARS-CoV-2 Spike protein that acts as indicators for antibody binding and use these hotspots to develop better neutralizing antibodies against SARS-CoV-2 and any future viral pandemics.