1
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Westendorf K, Žentelis S, Wang L, Foster D, Vaillancourt P, Wiggin M, Lovett E, van der Lee R, Hendle J, Pustilnik A, Sauder JM, Kraft L, Hwang Y, Siegel RW, Chen J, Heinz BA, Higgs RE, Kallewaard NL, Jepson K, Goya R, Smith MA, Collins DW, Pellacani D, Xiang P, de Puyraimond V, Ricicova M, Devorkin L, Pritchard C, O'Neill A, Dalal K, Panwar P, Dhupar H, Garces FA, Cohen CA, Dye JM, Huie KE, Badger CV, Kobasa D, Audet J, Freitas JJ, Hassanali S, Hughes I, Munoz L, Palma HC, Ramamurthy B, Cross RW, Geisbert TW, Menachery V, Lokugamage K, Borisevich V, Lanz I, Anderson L, Sipahimalani P, Corbett KS, Yang ES, Zhang Y, Shi W, Zhou T, Choe M, Misasi J, Kwong PD, Sullivan NJ, Graham BS, Fernandez TL, Hansen CL, Falconer E, Mascola JR, Jones BE, Barnhart BC. LY-CoV1404 (bebtelovimab) potently neutralizes SARS-CoV-2 variants. Cell Rep 2022; 39:110812. [PMID: 35568025 PMCID: PMC9035363 DOI: 10.1016/j.celrep.2022.110812] [Citation(s) in RCA: 212] [Impact Index Per Article: 106.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 03/24/2022] [Accepted: 04/20/2022] [Indexed: 01/18/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-neutralizing monoclonal antibodies (mAbs) can reduce the risk of hospitalization from coronavirus disease 2019 (COVID-19) when administered early. However, SARS-CoV-2 variants of concern (VOCs) have negatively affected therapeutic use of some authorized mAbs. Using a high-throughput B cell screening pipeline, we isolated LY-CoV1404 (bebtelovimab), a highly potent SARS-CoV-2 spike glycoprotein receptor binding domain (RBD)-specific antibody. LY-CoV1404 potently neutralizes authentic SARS-CoV-2, B.1.1.7, B.1.351, and B.1.617.2. In pseudovirus neutralization studies, LY-CoV1404 potently neutralizes variants, including B.1.1.7, B.1.351, B.1.617.2, B.1.427/B.1.429, P.1, B.1.526, B.1.1.529, and the BA.2 subvariant. Structural analysis reveals that the contact residues of the LY-CoV1404 epitope are highly conserved, except for N439 and N501. The binding and neutralizing activity of LY-CoV1404 is unaffected by the most common mutations at these positions (N439K and N501Y). The broad and potent neutralization activity and the relatively conserved epitope suggest that LY-CoV1404 has the potential to be an effective therapeutic agent to treat all known variants.
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Affiliation(s)
| | | | - Lingshu Wang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Denisa Foster
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - Peter Vaillancourt
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | | | - Erica Lovett
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | | | - Jörg Hendle
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - Anna Pustilnik
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - J Michael Sauder
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - Lucas Kraft
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | - Yuri Hwang
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | | | - Jinbiao Chen
- Eli Lilly and Company, Indianapolis, IN 46285, USA
| | | | | | | | - Kevin Jepson
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | - Rodrigo Goya
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | - Maia A Smith
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | | | | | - Ping Xiang
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | | | | | | | | | - Aoise O'Neill
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | - Kush Dalal
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | - Pankaj Panwar
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | | | | | - Courtney A Cohen
- U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD 21702, USA
| | - John M Dye
- U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD 21702, USA
| | - Kathleen E Huie
- U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD 21702, USA
| | - Catherine V Badger
- U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), Frederick, MD 21702, USA
| | - Darwyn Kobasa
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3E 3L5, Canada; University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Jonathan Audet
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3E 3L5, Canada; University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Joshua J Freitas
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - Saleema Hassanali
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - Ina Hughes
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - Luis Munoz
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - Holly C Palma
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | | | - Robert W Cross
- University of Manitoba, Winnipeg, MB R3T 2N2, Canada; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Thomas W Geisbert
- University of Manitoba, Winnipeg, MB R3T 2N2, Canada; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Vineet Menachery
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Kumari Lokugamage
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Viktoriya Borisevich
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Iliana Lanz
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | - Lisa Anderson
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | | | - Kizzmekia S Corbett
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Eun Sung Yang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yi Zhang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wei Shi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tongqing Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Misook Choe
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John Misasi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nancy J Sullivan
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Barney S Graham
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Carl L Hansen
- AbCellera Biologics Inc., Vancouver, BC V5Y 0A1, Canada
| | | | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bryan E Jones
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA.
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2
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Hsieh CL, Werner AP, Leist SR, Stevens LJ, Falconer E, Goldsmith JA, Chou CW, Abiona OM, West A, Westendorf K, Muthuraman K, Fritch EJ, Dinnon KH, Schäfer A, Denison MR, Chappell JD, Baric RS, Graham BS, Corbett KS, McLellan JS. Stabilized coronavirus spike stem elicits a broadly protective antibody. Cell Rep 2021; 37:109929. [PMID: 34710354 PMCID: PMC8519809 DOI: 10.1016/j.celrep.2021.109929] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 09/09/2021] [Accepted: 10/11/2021] [Indexed: 12/23/2022] Open
Abstract
Current coronavirus (CoV) vaccines primarily target immunodominant epitopes in the S1 subunit, which are poorly conserved and susceptible to escape mutations, thus threatening vaccine efficacy. Here, we use structure-guided protein engineering to remove the S1 subunit from the Middle East respiratory syndrome (MERS)-CoV spike (S) glycoprotein and develop stabilized stem (SS) antigens. Vaccination with MERS SS elicits cross-reactive β-CoV antibody responses and protects mice against lethal MERS-CoV challenge. High-throughput screening of antibody-secreting cells from MERS SS-immunized mice led to the discovery of a panel of cross-reactive monoclonal antibodies. Among them, antibody IgG22 binds with high affinity to both MERS-CoV and severe acute respiratory syndrome (SARS)-CoV-2 S proteins, and a combination of electron microscopy and crystal structures localizes the epitope to a conserved coiled-coil region in the S2 subunit. Passive transfer of IgG22 protects mice against both MERS-CoV and SARS-CoV-2 challenge. Collectively, these results provide a proof of principle for cross-reactive CoV antibodies and inform the development of pan-CoV vaccines and therapeutic antibodies.
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Affiliation(s)
- Ching-Lin Hsieh
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Anne P. Werner
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sarah R. Leist
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Laura J. Stevens
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | | | - Jory A. Goldsmith
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Chia-Wei Chou
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Olubukola M. Abiona
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ande West
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | | | - Ethan J. Fritch
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kenneth H. Dinnon
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alexandra Schäfer
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Mark R. Denison
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37212, USA,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - James D. Chappell
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Ralph S. Baric
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Barney S. Graham
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kizzmekia S. Corbett
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jason S. McLellan
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA,Corresponding author
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3
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Jones BE, Brown-Augsburger PL, Corbett KS, Westendorf K, Davies J, Cujec TP, Wiethoff CM, Blackbourne JL, Heinz BA, Foster D, Higgs RE, Balasubramaniam D, Wang L, Zhang Y, Yang ES, Bidshahri R, Kraft L, Hwang Y, Žentelis S, Jepson KR, Goya R, Smith MA, Collins DW, Hinshaw SJ, Tycho SA, Pellacani D, Xiang P, Muthuraman K, Sobhanifar S, Piper MH, Triana FJ, Hendle J, Pustilnik A, Adams AC, Berens SJ, Baric RS, Martinez DR, Cross RW, Geisbert TW, Borisevich V, Abiona O, Belli HM, de Vries M, Mohamed A, Dittmann M, Samanovic MI, Mulligan MJ, Goldsmith JA, Hsieh CL, Johnson NV, Wrapp D, McLellan JS, Barnhart BC, Graham BS, Mascola JR, Hansen CL, Falconer E. The neutralizing antibody, LY-CoV555, protects against SARS-CoV-2 infection in nonhuman primates. Sci Transl Med 2021; 13:eabf1906. [PMID: 33820835 PMCID: PMC8284311 DOI: 10.1126/scitranslmed.abf1906] [Citation(s) in RCA: 287] [Impact Index Per Article: 95.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 01/19/2021] [Accepted: 03/31/2021] [Indexed: 12/15/2022]
Abstract
Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) poses a public health threat for which preventive and therapeutic agents are urgently needed. Neutralizing antibodies are a key class of therapeutics that may bridge widespread vaccination campaigns and offer a treatment solution in populations less responsive to vaccination. Here, we report that high-throughput microfluidic screening of antigen-specific B cells led to the identification of LY-CoV555 (also known as bamlanivimab), a potent anti-spike neutralizing antibody from a hospitalized, convalescent patient with coronavirus disease 2019 (COVID-19). Biochemical, structural, and functional characterization of LY-CoV555 revealed high-affinity binding to the receptor-binding domain, angiotensin-converting enzyme 2 binding inhibition, and potent neutralizing activity. A pharmacokinetic study of LY-CoV555 conducted in cynomolgus monkeys demonstrated a mean half-life of 13 days and a clearance of 0.22 ml hour-1 kg-1, consistent with a typical human therapeutic antibody. In a rhesus macaque challenge model, prophylactic doses as low as 2.5 mg/kg reduced viral replication in the upper and lower respiratory tract in samples collected through study day 6 after viral inoculation. This antibody has entered clinical testing and is being evaluated across a spectrum of COVID-19 indications, including prevention and treatment.
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Affiliation(s)
- Bryan E Jones
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA.
| | | | - Kizzmekia S Corbett
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Julian Davies
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - Thomas P Cujec
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | | | | | | | - Denisa Foster
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | | | | | - Lingshu Wang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yi Zhang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Eun Sung Yang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Lucas Kraft
- AbCellera Biologics Inc., Vancouver, BC V5Y0A1, Canada
| | - Yuri Hwang
- AbCellera Biologics Inc., Vancouver, BC V5Y0A1, Canada
| | | | | | - Rodrigo Goya
- AbCellera Biologics Inc., Vancouver, BC V5Y0A1, Canada
| | - Maia A Smith
- AbCellera Biologics Inc., Vancouver, BC V5Y0A1, Canada
| | | | | | - Sean A Tycho
- AbCellera Biologics Inc., Vancouver, BC V5Y0A1, Canada
| | | | - Ping Xiang
- AbCellera Biologics Inc., Vancouver, BC V5Y0A1, Canada
| | | | | | - Marissa H Piper
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - Franz J Triana
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - Jorg Hendle
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | - Anna Pustilnik
- Lilly Biotechnology Center, Eli Lilly and Company, San Diego, CA 92121, USA
| | | | | | - Ralph S Baric
- University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - David R Martinez
- University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Robert W Cross
- Galveston National Laboratory and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Thomas W Geisbert
- Galveston National Laboratory and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Viktoriya Borisevich
- Galveston National Laboratory and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Olubukola Abiona
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hayley M Belli
- Department of Population Health, Division of Biostatistics, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Maren de Vries
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Adil Mohamed
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Meike Dittmann
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Marie I Samanovic
- NYU Langone Vaccine Center, Department of Medicine, Division of Infectious Diseases and Immunology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Mark J Mulligan
- NYU Langone Vaccine Center, Department of Medicine, Division of Infectious Diseases and Immunology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Jory A Goldsmith
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Ching-Lin Hsieh
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Nicole V Johnson
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Daniel Wrapp
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Jason S McLellan
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | | | - Barney S Graham
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Carl L Hansen
- AbCellera Biologics Inc., Vancouver, BC V5Y0A1, Canada
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Westendorf K, Žentelis S, Foster D, Vaillancourt P, Wiggin M, Lovett E, Hendle J, Pustilnik A, Sauder JM, Kraft L, Hwang Y, Siegel RW, Chen J, Heinz BA, Higgs RE, Kalleward N, Jepson K, Goya R, Smith MA, Collins DW, Pellacani D, Xiang P, de Puyraimond V, Ricicova M, Devorkin L, Pritchard C, O'Neill A, Cohen C, Dye J, Huie KI, Badger CV, Kobasa D, Audet J, Freitas JJ, Hassanali S, Hughes I, Munoz L, Palma HC, Ramamurthy B, Cross RW, Geisbert TW, Borisevich V, Lanz I, Anderson L, Sipahimalani P, Corbett KS, Wang L, Yang ES, Zhang Y, Shi W, Graham BS, Mascola JR, Fernandez TL, Hansen CL, Falconer E, Jones BE, Barnhart BC. LY-CoV1404 potently neutralizes SARS-CoV-2 variants. bioRxiv 2021. [PMID: 33972947 DOI: 10.1101/2021.04.30.442182] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
LY-CoV1404 is a highly potent, neutralizing, SARS-CoV-2 spike glycoprotein receptor binding domain (RBD)-specific antibody identified from a convalescent COVID-19 patient approximately 60 days after symptom onset. In pseudovirus studies, LY-CoV1404 retains potent neutralizing activity against numerous variants including B.1.1.7, B.1.351, B.1.427/B.1.429, P.1, and B.1.526 and binds to these variants in the presence of their underlying RBD mutations (which include K417N, L452R, E484K, and N501Y). LY-CoV1404 also neutralizes authentic SARS-CoV-2 in two different assays against multiple isolates. The RBD positions comprising the LY-CoV1404 epitope are highly conserved, with the exception of N439 and N501; notably the binding and neutralizing activity of LY-CoV1404 is unaffected by the most common mutations at these positions (N439K and N501Y). The breadth of variant binding, potent neutralizing activity and the relatively conserved epitope suggest that LY-CoV1404 is one in a panel of well-characterized, clinically developable antibodies that could be deployed rapidly to address current and emerging variants. New variant-resistant treatments such as LY-CoV1404 are desperately needed, given that some of the existing therapeutic antibodies are less effective or ineffective against certain variants and the impact of variants on vaccine efficacy is still poorly understood. In Brief LY-CoV1404 is a potent SARS-CoV-2-binding antibody that neutralizes all known variants of concern and whose epitope is rarely mutated. Highlights LY-CoV1404 potently neutralizes SARS-CoV-2 authentic virus and all known variants of concernNo loss of potency against current variantsBinding epitope on RBD of SARS-CoV-2 is rarely mutated in GISAID databaseBreadth of neutralizing activity and potency supports clinical development.
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5
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Jones BE, Brown-Augsburger PL, Corbett KS, Westendorf K, Davies J, Cujec TP, Wiethoff CM, Blackbourne JL, Heinz BA, Foster D, Higgs RE, Balasubramaniam D, Wang L, Bidshahri R, Kraft L, Hwang Y, Žentelis S, Jepson KR, Goya R, Smith MA, Collins DW, Hinshaw SJ, Tycho SA, Pellacani D, Xiang P, Muthuraman K, Sobhanifar S, Piper MH, Triana FJ, Hendle J, Pustilnik A, Adams AC, Berens SJ, Baric RS, Martinez DR, Cross RW, Geisbert TW, Borisevich V, Abiona O, Belli HM, de Vries M, Mohamed A, Dittmann M, Samanovic M, Mulligan MJ, Goldsmith JA, Hsieh CL, Johnson NV, Wrapp D, McLellan JS, Barnhart BC, Graham BS, Mascola JR, Hansen CL, Falconer E. LY-CoV555, a rapidly isolated potent neutralizing antibody, provides protection in a non-human primate model of SARS-CoV-2 infection. bioRxiv 2020. [PMID: 33024963 DOI: 10.1101/2020.09.30.318972] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SARS-CoV-2 poses a public health threat for which therapeutic agents are urgently needed. Herein, we report that high-throughput microfluidic screening of antigen-specific B-cells led to the identification of LY-CoV555, a potent anti-spike neutralizing antibody from a convalescent COVID-19 patient. Biochemical, structural, and functional characterization revealed high-affinity binding to the receptor-binding domain, ACE2 binding inhibition, and potent neutralizing activity. In a rhesus macaque challenge model, prophylaxis doses as low as 2.5 mg/kg reduced viral replication in the upper and lower respiratory tract. These data demonstrate that high-throughput screening can lead to the identification of a potent antiviral antibody that protects against SARS-CoV-2 infection. One Sentence Summary LY-CoV555, an anti-spike antibody derived from a convalescent COVID-19 patient, potently neutralizes SARS-CoV-2 and protects the upper and lower airways of non-human primates against SARS-CoV-2 infection.
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6
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Sanders AD, Falconer E, Hills M, Spierings DCJ, Lansdorp PM. Single-cell template strand sequencing by Strand-seq enables the characterization of individual homologs. Nat Protoc 2017; 12:1151-1176. [PMID: 28492527 DOI: 10.1038/nprot.2017.029] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The ability to distinguish between genome sequences of homologous chromosomes in single cells is important for studies of copy-neutral genomic rearrangements (such as inversions and translocations), building chromosome-length haplotypes, refining genome assemblies, mapping sister chromatid exchange events and exploring cellular heterogeneity. Strand-seq is a single-cell sequencing technology that resolves the individual homologs within a cell by restricting sequence analysis to the DNA template strands used during DNA replication. This protocol, which takes up to 4 d to complete, relies on the directionality of DNA, in which each single strand of a DNA molecule is distinguished based on its 5'-3' orientation. Culturing cells in a thymidine analog for one round of cell division labels nascent DNA strands, allowing for their selective removal during genomic library construction. To preserve directionality of template strands, genomic preamplification is bypassed and labeled nascent strands are nicked and not amplified during library preparation. Each single-cell library is multiplexed for pooling and sequencing, and the resulting sequence data are aligned, mapping to either the minus or plus strand of the reference genome, to assign template strand states for each chromosome in the cell. The major adaptations to conventional single-cell sequencing protocols include harvesting of daughter cells after a single round of BrdU incorporation, bypassing of whole-genome amplification, and removal of the BrdU+ strand during Strand-seq library preparation. By sequencing just template strands, the structure and identity of each homolog are preserved.
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Affiliation(s)
- Ashley D Sanders
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Ester Falconer
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Mark Hills
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada
| | - Diana C J Spierings
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands
| | - Peter M Lansdorp
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, Canada.,European Research Institute for the Biology of Ageing, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands.,Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
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7
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Porubský D, Sanders AD, van Wietmarschen N, Falconer E, Hills M, Spierings DCJ, Bevova MR, Guryev V, Lansdorp PM. Direct chromosome-length haplotyping by single-cell sequencing. Genome Res 2016; 26:1565-1574. [PMID: 27646535 PMCID: PMC5088598 DOI: 10.1101/gr.209841.116] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Accepted: 09/15/2016] [Indexed: 11/25/2022]
Abstract
Haplotypes are fundamental to fully characterize the diploid genome of an individual, yet methods to directly chart the unique genetic makeup of each parental chromosome are lacking. Here we introduce single-cell DNA template strand sequencing (Strand-seq) as a novel approach to phasing diploid genomes along the entire length of all chromosomes. We demonstrate this by building a complete haplotype for a HapMap individual (NA12878) at high accuracy (concordance 99.3%), without using generational information or statistical inference. By use of this approach, we mapped all meiotic recombination events in a family trio with high resolution (median range ∼14 kb) and phased larger structural variants like deletions, indels, and balanced rearrangements like inversions. Lastly, the single-cell resolution of Strand-seq allowed us to observe loss of heterozygosity regions in a small number of cells, a significant advantage for studies of heterogeneous cell populations, such as cancer cells. We conclude that Strand-seq is a unique and powerful approach to completely phase individual genomes and map inheritance patterns in families, while preserving haplotype differences between single cells.
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Affiliation(s)
- David Porubský
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Ashley D Sanders
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC V5Z 1L3, Canada
| | - Niek van Wietmarschen
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Ester Falconer
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC V5Z 1L3, Canada
| | - Mark Hills
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC V5Z 1L3, Canada
| | - Diana C J Spierings
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Marianna R Bevova
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Victor Guryev
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Peter M Lansdorp
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC V5Z 1L3, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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Sanders AD, Hills M, Porubský D, Guryev V, Falconer E, Lansdorp PM. Characterizing polymorphic inversions in human genomes by single-cell sequencing. Genome Res 2016; 26:1575-1587. [PMID: 27472961 PMCID: PMC5088599 DOI: 10.1101/gr.201160.115] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 06/13/2016] [Indexed: 12/23/2022]
Abstract
Identifying genomic features that differ between individuals and cells can help uncover the functional variants that drive phenotypes and disease susceptibilities. For this, single-cell studies are paramount, as it becomes increasingly clear that the contribution of rare but functional cellular subpopulations is important for disease prognosis, management, and progression. Until now, studying these associations has been challenged by our inability to map structural rearrangements accurately and comprehensively. To overcome this, we coupled single-cell sequencing of DNA template strands (Strand-seq) with custom analysis software to rapidly discover, map, and genotype genomic rearrangements at high resolution. This allowed us to explore the distribution and frequency of inversions in a heterogeneous cell population, identify several polymorphic domains in complex regions of the genome, and locate rare alleles in the reference assembly. We then mapped the entire genomic complement of inversions within two unrelated individuals to characterize their distinct inversion profiles and built a nonredundant global reference of structural rearrangements in the human genome. The work described here provides a powerful new framework to study structural variation and genomic heterogeneity in single-cell samples, whether from individuals for population studies or tissue types for biomarker discovery.
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Affiliation(s)
- Ashley D Sanders
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, V5Z 1L3, Canada
| | - Mark Hills
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, V5Z 1L3, Canada
| | - David Porubský
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Centre Groningen, NL-9713 AV Groningen, The Netherlands
| | - Victor Guryev
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Centre Groningen, NL-9713 AV Groningen, The Netherlands
| | - Ester Falconer
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, V5Z 1L3, Canada
| | - Peter M Lansdorp
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia, V5Z 1L3, Canada.,European Research Institute for the Biology of Ageing, University of Groningen, University Medical Centre Groningen, NL-9713 AV Groningen, The Netherlands.,Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
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9
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van den Bos H, Spierings DCJ, Taudt A, Bakker B, Porubský D, Falconer E, Novoa C, Halsema N, Kazemier HG, Hoekstra-Wakker K, Guryev V, den Dunnen WFA, Foijer F, Colomé-Tatché M, Boddeke HWGM, Landsdorp PM. Erratum to: Single-cell whole genome sequencing reveals no evidence for common aneuploidy in normal and Alzheimer's disease neurons. Genome Biol 2016; 17:143. [PMID: 27363435 PMCID: PMC4928312 DOI: 10.1186/s13059-016-1015-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 06/22/2016] [Indexed: 11/10/2022] Open
Affiliation(s)
- Hilda van den Bos
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands
| | - Diana C J Spierings
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands
| | - Aaron Taudt
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands.,Institute for Computational Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Bjorn Bakker
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands
| | - David Porubský
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands
| | - Ester Falconer
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC, V5Z 1L3, Canada
| | - Carolina Novoa
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC, V5Z 1L3, Canada
| | - Nancy Halsema
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands
| | - Hinke G Kazemier
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands
| | - Karina Hoekstra-Wakker
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands
| | - Victor Guryev
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands
| | - Wilfred F A den Dunnen
- Section of Pathology, Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands
| | - Floris Foijer
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands
| | - Maria Colomé-Tatché
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands.,Institute for Computational Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Hendrikus W G M Boddeke
- Section Medical Physiology, Department of Neuroscience, University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands
| | - Peter M Landsdorp
- European Research Institute for the Biology of Ageing (ERIBA), University of Groningen, University Medical Center Groningen, 9713, AV, Groningen, The Netherlands. .,Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC, V5Z 1L3, Canada. .,Division of Hematology, Department of Medicine, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
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10
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Bamber A, Cunniffe J, Nayar D, Gangul R, Falconer E. Effectiveness of introducing blood culture collection packs to reduce contamination rates. Br J Biomed Sci 2016; 66:6-9. [DOI: 10.1080/09674845.2009.11730236] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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11
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Alexandridis E, Inglis S, McAvoy NC, Falconer E, Graham C, Hayes PC, Plevris JN. Randomised clinical study: comparison of acceptability, patient tolerance, cardiac stress and endoscopic views in transnasal and transoral endoscopy under local anaesthetic. Aliment Pharmacol Ther 2014; 40:467-76. [PMID: 25039412 DOI: 10.1111/apt.12866] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 06/10/2014] [Accepted: 06/19/2014] [Indexed: 12/15/2022]
Abstract
BACKGROUND Transnasal endoscopy (TNE) with ultrathin endoscopes has been advocated as an attractive alternative, for diagnostic upper endoscopy. AIM To assess tolerability, acceptability and quality of TNE, in comparison with standard upper endoscopy (SOGD, standard oesophago-gastro-duodenoscopy) under local anaesthetic. METHODS We prospectively recruited 157 patients (83 females/74 males) mean age 57 years. The Fujinon EG530N (5.9 mm) and EG530WR (9.4 mm) endoscopes were used. The endoscopist and all patients completed detailed questionnaires regarding tolerability, acceptance and quality of endoscopy using standard visual analogue scales (VAS). Oxygen saturation (SaO2 ), heart rate (HR) and systolic blood pressure (SBP) were recorded. Quality of biopsies was evaluated. RESULTS Analysis included 161 procedures (TNE:79, SOGD:82) with duodenal intubation achieved in all patients. VAS scores for patient comfort were significantly better in the TNE group (7.3 vs. 5.3 respectively, P < 0.001). Twenty patients with previous experience of standard endoscopy were randomised to TNE and 19 of them (95.5%) preferred the TNE. Gagging was significantly less in the TNE group (0.12 vs. 3.41 respectively, P < 0.001). Cardiovascular stress was significantly less in the TNE group irrespective of the degree of gagging or comfort. TNE biopsies were smaller, but adequate for definitive diagnosis, similarly to standard endoscopy. CONCLUSIONS Transnasal endoscopy is superior to SOGD in terms of comfort and patient acceptance with significantly less cardiovascular stress. TNE can routinely be used as alternative to SOGD under local anaesthetic, for diagnosis and should be preferentially offered in cardiorespiratory compromised patients.
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Affiliation(s)
- E Alexandridis
- Centre for Liver and Digestive Disorders, The Royal Infirmary of Edinburgh, University of Edinburgh, Edinburgh, UK
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12
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Falconer E. Looking beyond the post-genomic era. Genome Biol 2013; 14:313. [PMID: 24286127 PMCID: PMC4053758 DOI: 10.1186/gb4138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
A report on BioMed Central’s fourth annual Beyond the Genome conference held at the University of California, San Francisco Mission Bay Conference Center, USA, 1–3 October 2013.
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13
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Abstract
Semi-conservative replication ensures that the DNA sequence of sister chromatids is identical except for replication errors and variation in the length of telomere repeats resulting from replicative losses and variable end processing. What happens with the various epigenetic marks during DNA replication is less clear. Many chromatin marks are likely to be copied onto both sister chromatids in conjunction with DNA replication, whereas others could be distributed randomly between sister chromatids. Epigenetic differences between sister chromatids could also emerge in a more predictable manner, for example, following processes that are associated with lagging strand DNA replication. The resulting epigenetic differences between sister chromatids could result in different gene expression patterns in daughter cells. This possibility has been difficult to test because techniques to distinguish between parental sister chromatids require analysis of single cells and are not obvious. Here, we briefly review the topic of sister chromatid epigenetics and discuss how the identification of sister chromatids in cells could change the way we think about asymmetric cell divisions and stochastic variation in gene expression between cells in general and paired daughter cells in particular.
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Affiliation(s)
- Peter M Lansdorp
- Terry Fox Laboratory, BC Cancer Agency, Vancouver, British Columbia, Canada.
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14
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Beck SA, Falconer E, Catching A, Hodgson JW, Brock HW. Cell cycle defects in polyhomeotic mutants are caused by abrogation of the DNA damage checkpoint. Dev Biol 2010; 339:320-8. [PMID: 20045683 DOI: 10.1016/j.ydbio.2009.12.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 10/30/2009] [Accepted: 12/19/2009] [Indexed: 12/31/2022]
Abstract
Polycomb group (PcG) genes are required for heritable silencing of target genes. Many PcG mutants have chromatin bridges and other mitotic defects in early embryos. These phenotypes can arise from defects in S phase or mitosis, so the phenotype does not show when PcG proteins act in cell cycle regulation. We analyzed the cell cycle role of the proximal subunit of Polyhomeotic (PhP) in Drosophila. Time-lapse imaging reveals that chromatin bridges formed during mitosis are able to resolve but sometimes result in chromosome breakage. Chromosome bridging is also observed in canonical cell cycles occurring in larval brains and is therefore not unique to the rapid embryonic cycles. PhP colocalizes with chromatin in S phase but not in mitosis in early embryos, indicating a direct role in DNA synthesis. Time lapse imaging of ph(p) mutants reveals an acceleration of S phase, showing that ph(p) regulates S phase length. Like ph(p) mutations, mutations in DNA damage checkpoints result in S phase acceleration. Consistent with this model, mutations in ph do not affect DNA synthesis rates, but exhibit impaired ability to block cell cycle progression following exposure to gamma-rays. Our data show that the mitotic defects of ph(p) are caused by defects in the DNA damage response that occurs after DNA replication in S phase, and we propose that PhP has a direct role in DNA damage repair.
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Affiliation(s)
- Samantha A Beck
- Molecular Epigenetics Group, Department of Zoology, University of BC, Life Sciences Centre, 2350 Health Sciences Mall Vancouver, BC, Canada V6T 1Z3
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15
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Falconer E, Chavez EA, Henderson A, Poon SSS, McKinney S, Brown L, Huntsman DG, Lansdorp PM. Identification of sister chromatids by DNA template strand sequences. Nature 2009; 463:93-7. [PMID: 20016487 DOI: 10.1038/nature08644] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 11/06/2009] [Indexed: 01/06/2023]
Abstract
It is generally assumed that sister chromatids are genetically and functionally identical and that segregation to daughter cells is a random process. However, functional differences between sister chromatids regulate daughter cell fate in yeast and sister chromatid segregation is not random in Escherichia coli. Differentiated sister chromatids, coupled with non-random segregation, have been proposed to regulate cell fate during the development of multicellular organisms. This hypothesis has not been tested because molecular features to reliably distinguish between sister chromatids are not obvious. Here we show that parental 'Watson' and 'Crick' DNA template strands can be identified in sister chromatids of murine metaphase chromosomes using CO-FISH (chromosome orientation fluorescence in situ hybridization) with unidirectional probes specific for centromeric and telomeric repeats. All chromosomes were found to have a uniform orientation with the 5' end of the short arm on the same strand as T-rich major satellite repeats. The invariable orientation of repetitive DNA was used to differentially label sister chromatids and directly study mitotic segregation patterns in different cell types. Whereas sister chromatids appeared to be randomly distributed between daughter cells in cultured lung fibroblasts and embryonic stem cells, significant non-random sister chromatid segregation was observed in a subset of colon crypt epithelial cells, including cells outside positions reported for colon stem cells. Our results establish that DNA template sequences can be used to distinguish sister chromatids and follow their mitotic segregation in vivo.
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Affiliation(s)
- Ester Falconer
- Terry Fox Laboratory, B.C. Cancer Agency, Vancouver, British Columbia V5Z 1L3, Canada
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16
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Felmingham K, Kemp AH, Williams L, Falconer E, Olivieri G, Peduto A, Bryant R. Dissociative responses to conscious and non-conscious fear impact underlying brain function in post-traumatic stress disorder. Psychol Med 2008; 38:1771-1780. [PMID: 18294420 DOI: 10.1017/s0033291708002742] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Dissociative reactions in post-traumatic stress disorder (PTSD) have been regarded as strategic responses that limit arousal. Neuroimaging studies suggest distinct prefrontal responses in individuals displaying dissociative and hyperarousal responses to threat in PTSD. Increased prefrontal activity may reflect enhanced regulation of limbic arousal networks in dissociation. If dissociation is a higher-order regulatory response to threat, there may be differential responses to conscious and automatic processing of threat stimuli. This study addresses this question by examining the impact of dissociation on fear processing at different levels of awareness. METHOD Functional magnetic resonance imaging (fMRI) with a 1.5-T scanner was used to examine activation to fearful (versus neutral) facial expressions during consciously attended and non-conscious (using backward masking) conditions in 23 individuals with PTSD. Activation in 11 individuals displaying non-dissociative reactions was compared to activation in 12 displaying dissociative reactions to consciously and non-consciously perceived fear stimuli. RESULTS Dissociative PTSD was associated with enhanced activation in the ventral prefrontal cortex for conscious fear, and in the bilateral amygdala, insula and left thalamus for non-conscious fear compared to non-dissociative PTSD. Comparatively reduced activation in the dissociative group was apparent in dorsomedial prefrontal regions for conscious fear faces. CONCLUSIONS These findings confirm our hypotheses of enhanced prefrontal activity to conscious fear and enhanced activity in limbic networks to non-conscious fear in dissociative PTSD. This supports the theory that dissociation is a regulatory strategy invoked to cope with extreme arousal in PTSD, but this strategy appears to function only during conscious processing of threat.
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Affiliation(s)
- K Felmingham
- Brain Dynamics Centre, Westmead Millennium Institute, Westmead Hospital, Australia.
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