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Neutralizing antibody and soluble ACE2 inhibition of a replication-competent VSV-SARS-CoV-2 and a clinical isolate of SARS-CoV-2

Cell Host & Microbe, 2020-07-03

Video Abstract (AI generated) Paper Preprint Cell Host & Microbe

Antibody-based interventions against SARS-CoV-2 could limit morbidity, mortality, and possibly disrupt epidemic transmission. An anticipated correlate of such countermeasures is the level of neutralizing antibodies against the SARS-CoV-2 spike protein, yet there is no consensus as to which assay should be used for such measurements. Using an infectious molecular clone of vesicular stomatitis virus (VSV) that expresses eGFP as a marker of infection, we replaced the glycoprotein gene (G) with the spike protein of SARS-CoV-2 (VSV-eGFP-SARS-CoV-2) and developed a high-throughput imaging-based neutralization assay at biosafety level 2. We also developed a focus reduction neutralization test with a clinical isolate of SARS-CoV-2 at biosafety level 3. We compared the neutralizing activities of monoclonal and polyclonal antibody preparations, as well as ACE2-Fc soluble decoy protein in both assays and find an exceptionally high degree of concordance. The two assays will help define correlates of protection for antibody-based countermeasures including therapeutic antibodies, immune γ-globulin or plasma preparations, and vaccines against SARS-CoV-2. Replication-competent VSV-eGFP-SARS-CoV-2 provides a rapid assay for testing inhibitors of SARS-CoV-2 mediated entry that can be performed in 7.5 hours under reduced biosafety containment. ### Competing Interest Statement M.S.D. is a consultant for Inbios, Vir Biotechnology, NGM Biopharmaceuticals, and on the Scientific Advisory Board of Moderna. D.C. and H.W.V. are employees of Vir Biotechnology Inc. and may hold shares in Vir Biotechnology Inc. S.P.J.W. and P.W.R. have filed a disclosure with Washington University for the recombinant VSV.

Cholesterol 25-hydroxylase suppresses SARS-CoV-2 replication by blocking membrane fusion

Video Abstract (AI generated) Paper Preprint

Cholesterol 25-hydroxylase (CH25H) is an interferon-stimulated gene (ISG) that shows broad antiviral activities against a wide range of enveloped viruses. Here, using an ISG screen against VSV-SARS-CoV and VSV-SARS-CoV-2 chimeric viruses, we identified CH25H and its enzymatic product 25-hydroxycholesterol (25HC) as potent inhibitors of virus replication. Mechanistically, internalized 25HC accumulates in the late endosomes and blocks cholesterol export, thereby restricting SARS-CoV-2 spike protein catalyzed membrane fusion. Our results highlight a unique antiviral mechanism of 25HC and provide the molecular basis for its possible therapeutic development. ### Competing Interest Statement M.S.D. is a consultant for Inbios, Eli Lilly, Vir Biotechnology, NGM Biopharmaceuticals, and Emergent BioSolutions and on the Scientific Advisory Board of Moderna. The Diamond laboratory at Washington University School of Medicine has received sponsored research agreements from Moderna. Invention disclosure filed with Washington University in St. Louis for the recombinant VSV-SARS-CoV-2 used herein.

TMPRSS2 and TMPRSS4 mediate SARS-CoV-2 infection of human small intestinal enterocytes

Science Immunology, 2020-05-13

Video Abstract (AI generated) Paper Preprint Science Immunology

Both gastrointestinal symptoms and fecal shedding of SARS-CoV-2 RNA have been frequently observed in COVID-19 patients. However, whether SARS-CoV-2 replicate in the human intestine and its clinical relevance to potential fecal-oral transmission remain unclear. Here, we demonstrate productive infection of SARS-CoV-2 in ACE2+ mature enterocytes in human small intestinal enteroids. In addition to TMPRSS2, another mucosa-specific serine protease, TMPRSS4, also enhanced SARS-CoV-2 spike fusogenic activity and mediated viral entry into host cells. However, newly synthesized viruses released into the intestinal lumen were rapidly inactivated by human colonic fluids and no infectious virus was recovered from the stool specimens of COVID-19 patients. Our results highlight the intestine as a potential site of SARS-CoV-2 replication, which may contribute to local and systemic illness and overall disease progression. ### Competing Interest Statement The authors have declared no competing interest.

Nitazoxanide and JIB-04 have broad-spectrum antiviral activity and inhibit SARS-CoV-2 replication in cell culture and coronavirus pathogenesis in a pig model

Video Abstract (AI generated) Paper Preprint

Pathogenic coronaviruses represent a major threat to global public health. Here, using a recombinant reporter virus-based compound screening approach, we identified several small-molecule inhibitors that potently block the replication of the newly emerged severe acute respiratory syndrome virus 2 (SARS-CoV-2). Two compounds, nitazoxanide and JIB-04 inhibited SARS-CoV-2 replication in Vero E6 cells with an EC50 of 4.90 μM and 0.69 μM, respectively, with specificity indices of greater than 150. Both inhibitors had in vitro antiviral activity in multiple cell types against some DNA and RNA viruses, including porcine transmissible gastroenteritis virus. In an in vivo porcine model of coronavirus infection, administration of JIB-04 reduced virus infection and associated tissue pathology, which resulted in improved body weight gain and survival. These results highlight the potential utility of nitazoxanide and JIB-04 as antiviral agents against SARS-CoV-2 and other viral pathogens. ### Competing Interest Statement The Boon laboratory has scientific research agreements with AI therapeutics, Greenlight Biosciences and Nano Targeting & Therapy Biopharma Inc. M.S.D. is a consultant for Inbios, Eli Lilly, Vir Biotechnology, NGM Biopharmaceuticals, and Emergent BioSolutions and on the Scientific Advisory Boards of Moderna and Immunome. The Diamond laboratory at Washington University School of Medicine has received unrelated sponsored research agreements from Moderna, Vir Biotechnology, and Emergent BioSolutions.